Currently, with the rapid development of China's industry, the demand for electrical power rises substantially, and considering the request of environment protection, China has progressively expanded investment on nuclear power, hydropower, and solar power generation. Large hydropower generator or nuclear power generator has high requirements on electrical steels, especially on the insulation thereof. Therefore, a technique for applying extremely thick environment-friendly insulation coating on surfaces of strip steels is needed.
Currently, coatings from Dupont, Rembrandtin, Kluthe and the like are mainly used as the extremely thick insulation coating on surfaces of electrical steels. Usually, a vertical double-roller coating machine is utilized to apply coating, wherein the coating roller is a grooved or slotted roller, and it is also a driven roller, being rotated by the motion of the strip steel. If the speed of the process line fluctuates, the film thickness control may be affected adversely, resulting in low precision of coating thickness. Besides, the coating produced by the grooved roller is prone to being uneven, causing non-uniformity of insulation, and failing to meet the requirements of lamination. The ways of “baking” after coating include primarily induction heating, hot-air drying, infrared heating and near-infrared heating, wherein the induction heating equipments are difficult to install, and it may result in uneven heating in width of strip steels, thereby causing non-uniform coating properties; while the infrared heating device and the near-infrared heating device have a high heating precision, they need tremendous investment, and feature complicated processes, which may go against reducing production cost.